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| United States Patent |
5,634,860
|
|
McIntosh
, et al.
|
June 3, 1997
|
Golf club and shaft therefor
Abstract
A golf club 10 includes a shaft 12 with a grip 14 assembled on a butt end
16 of the shaft. A club head 18 is mounted on a tip end 20 of the shaft
12. The shaft 12 is composed of steel and is formed with an intermediate
section 22 having a plurality of sections 22a through 22n of decreasing
diameter from the butt end 16 toward the tip end 20. A bulge 24 is formed
in the shaft 12 near an inboard extremity of the tip end 20. The bulge 24
is formed with a central cylindrical section 26 with three cylindrical
step surfaces 30, 32 and 34 at one axial end of the section 26 and three
step surfaces 36, 38 and 40 at the opposite axial end of the section 26.
The diameter of the central section 26 is greater than the diameter of the
immediately adjacent portions of the shaft 12. Also, the diameters of each
set of the three step surfaces at each end of the central section 26, that
is surfaces 30, 32 and 34 at one end and surfaces 36, 38 and 40 at the
other end, are successively greater than the adjacent portion of the
shaft, but less than the diameter of the central section 26.
| Inventors:
|
McIntosh; William R. (Bartlett, TN);
Kitchens; Jeffrey E. (Cordova, TN)
|
| Assignee:
|
Emhart Inc. (Newark, DE)
|
| Appl. No.:
|
614589 |
| Filed:
|
March 13, 1996 |
| Current U.S. Class: |
473/318; 473/320; 473/323 |
| Intern'l Class: |
A63B 053/12 |
| Field of Search: |
473/316,317,318,319,320,321,322,256,226,323
273/DIG. 7,DIG. 23
|
References Cited
U.S. Patent Documents
| 1418039 | May., 1922 | Tousey.
| |
| 1486572 | Mar., 1924 | Forsyth.
| |
| 1688473 | Oct., 1928 | Sippel.
| |
| 1781116 | Nov., 1930 | Link et al.
| |
| 1796274 | Mar., 1931 | Bryant.
| |
| 1980031 | Nov., 1934 | Brading.
| |
| 1997853 | Apr., 1935 | Buhrke.
| |
| 2124534 | Jul., 1938 | Barnhart.
| |
| 2153550 | Apr., 1939 | Cowdery.
| |
| 3764137 | Oct., 1973 | Petro.
| |
| 4097626 | Jun., 1978 | Tennant.
| |
| 4131701 | Dec., 1978 | Van Auken.
| |
| 4330126 | May., 1982 | Rumble.
| |
| 4415156 | Nov., 1983 | Jorgensen.
| |
| 5251896 | Oct., 1993 | Gerlach.
| |
| 5277423 | Jan., 1994 | Artus.
| |
| 5294119 | Mar., 1994 | Vincent.
| |
| 5297791 | Mar., 1994 | Negishi.
| |
| 5316299 | May., 1994 | Feche.
| |
| 5467984 | Nov., 1995 | Veux.
| |
| 5496028 | Mar., 1996 | Chien.
| |
| 5551691 | Sep., 1996 | Harada | 473/318.
|
| Foreign Patent Documents |
| 1259879 | Oct., 1989 | JP.
| |
| 254121 | Nov., 1995 | TW.
| |
| 2146906 | May., 1983 | GB.
| |
| 2250443 | Jun., 1992 | GB.
| |
Primary Examiner: Passaniti; Sebastiano
Attorney, Agent or Firm: Murphy; E. D.
Claims
What is claimed is:
1. A golf club shaft, which comprises:
a metallic body extending longitudinally along an axis thereof;
the body formed with a butt end formed at one end thereof having an inboard
extremity of a prescribed diameter and an outboard extremity;
the body formed with a tip end formed at an end thereof axially opposite
the butt end and spaced axially therefrom and having an inboard extremity
of a diameter less than the prescribed diameter and an outboard extremity;
the body formed with an intermediate section which extends from the inboard
extremity of the butt end toward the tip end wherein the diameter of an
end of the intermediate section which joins the butt end is the same as
the prescribed diameter and the diameter of an opposite end of the
intermediate section is less than the prescribed diameter;
a bulge formed in the body along the axis thereof; and
the bulge formed with radially-outward-extending axially-spaced stepped
portions joined with opposite ends of a central shell-like portion between
the stepped portions said central shell-like portion extending radially
from the axis of the body by a distance which is greater than the diameter
of at least the stepped portions immediately adjacent the opposite ends of
the central shell-like portion.
2. The golf club shaft as set forth in claim 1, wherein the bulge is formed
in the tip end.
3. The golf club shaft as set forth in claim 1, wherein the bulge is formed
in the intermediate section.
4. The golf club shaft as set forth in claim 1, wherein the bulge is formed
with an axial length where a first portion of the axial length is located
in the tip end and a second remaining portion of the axial length is
located in the intermediate section.
5. The golf club shaft as set forth in claim 1, wherein the central
shell-like portion extends radially from the axis of the body by a
distance which is greater than the diameter of the portions of the body
immediately adjacent the bulge.
6. The golf club shaft as set forth in claim 1, wherein the stepped
portions of the bulge include at least one step at each end of the bulge
which extends radially from the axis of the body by a distance greater
than the diameter of the portions of the body immediately adjacent the
bulge.
7. The golf club shaft as set forth in claim 1, wherein the stepped
portions of the bulge include three steps at each end of the bulge which
extend axially between the immediately adjacent portion of the body and
the central shell-like portion of the bulge and which extend radially from
the axis of the body by a distance greater than the diameter of the
portions of the body immediately adjacent the bulge.
8. The golf club shaft as set forth in claim 7, wherein the three steps at
each end of the bulge include:
a first step joined at a first end thereof with the immediately adjacent
portion of the body and extending radially outward from the axis of the
body by a first distance which is greater than the diameter of the
adjacent portion of the body;
a second step joined at a first end thereof with a second end of the first
step and extending radially outward from the axis of the body by a second
distance greater than the first distance,
a third step joined at a first end thereof with a second end of the second
step and extending radially outward from the axis of the body by a third
distance greater than the second distance; and
a second end of the third step joined with a respective end of the central
shell-like portion of the bulge.
9. The golf club shaft as set forth in claim 8, wherein the opposite ends
of the central shell-like portion are joined with respective ones of the
third steps and the central portion extends radially outward from the axis
of the body by a distance greater than the third distance.
10. The golf club shaft as set forth in claim 8, wherein each of the first,
second and third steps extend circumferentially around the axis of the
body.
11. The golf club shaft as set forth in claim 10, wherein the central
shell-like portion extends circumferentially around the axis of the body.
12. The golf club shaft as set forth in claim 1, wherein the butt end is
formed with a uniform diameter from the outboard extremity to the inboard
extremity thereof.
13. The golf club shaft as set forth in claim 1, wherein the tip end is
formed with a uniform diameter from the outboard extremity to the inboard
extremity thereof.
14. The golf club shaft as set forth in claim 1, wherein the intermediate
section is formed with a plurality of cylindrical segments of successively
decreasing diameters beginning with the segment of greatest diameter which
is joined with the inboard extremity of the butt end to the segment of
smallest diameter which is joined with the inboard extremity of the tip
end.
15. A golf club shaft, which comprises:
a metallic tube;
a butt end at one end of the tube and a tip end at another end of the tube
spaced axially therefrom;
at least a portion of the tube between the butt and tip ends thereof being
formed with a first end diameter at a first end thereof which is closer to
the butt end and a second end diameter at a second end thereof with a
diameter smaller than the first diameter and closer to the tip end;
a section of the tube extends between the first end and the second end of
the portion and is formed with successively smaller diameters from the
first end to the second end within a range of diameters between the first
end diameter and the second end diameter;
a bulge formed in the tube between the second end of the portion and the
tip end;
the bulge formed with a central cylindrical section of a prescribed axial
length and a prescribed diameter greater than the second end diameter;
the bulge further formed with a pair of first step surfaces with a
respective one of the first step surfaces joined to each end of the
central section and having a first step diameter which is less than the
central section diameter and greater than the second end diameter;
the bulge further formed with a pair of second step surfaces with
respective ones of the second step surfaces joined at one of two ends
thereof to respective ones of the pair of first step surfaces;
one of the pair of second step surfaces joined at another of the two ends
thereof with the second end of the portion of the tube and the other of
the pair of second step surfaces joined at another of the two ends thereof
with the tip end of the tube; and
the pair of second step surfaces being formed with a second step diameter
which is less than the first step diameter and greater than the second end
diameter.
16. A golf club, which comprises:
a golf club shaft having a metallic body extending longitudinally along an
axis of the body;
the body formed with a butt end formed at one end thereof having an inboard
extremity of a prescribed diameter and an outboard extremity;
the body formed with a tip end formed at an end thereof axially opposite
the butt end and spaced axially therefrom and having an inboard extremity
of a diameter less than the prescribed diameter and an outboard extremity;
the body formed with an intermediate section which extends between the
inboard extremities of the butt end and the tip end wherein the diameter
of an end of the intermediate section which joins the butt end is the same
as the prescribed diameter and the diameter of an end of the section which
joins the tip end is the same as the diameter of the inboard extremity of
the tip end;
a bulge formed in the body along the axis thereof;
the bulge formed with radially-outward-extending axially-spaced stepped
portions joined with opposite ends of a central shell-like portion between
the stepped portions said central shell-like portion extending radially
from the axis of the body by a distance which is greater than the diameter
of at least the stepped portions immediately adjacent the opposite ends of
the central shell-like portion;
a grip assembled on the butt end of the body; and
a club head assembled on the tip end of the body.
17. The golf club as set forth in claim 16, wherein the stepped portions of
the bulge include at least one step at each end of the bulge which extends
radially from the axis of the body by a distance greater than the diameter
of the portions of the body immediately adjacent the bulge.
18. The golf club as set forth in claim 16 wherein the stepped portions of
the bulge include three steps at each end of the bulge which extend
axially between the immediately adjacent portion of the body and the
central shell-like portion of the bulge and which extend radially from the
axis of the body by a distance greater than the diameter of the portions
of the body immediately adjacent the bulge.
19. The golf club as set forth in claim 18, wherein the three steps at each
end of the bulge include:
a first step Joined at a first end thereof with the immediately adjacent
portion of the body and extending radially outward from the axis of the
body by a first distance which is greater than the diameter of the
adjacent portion of the body;
a second step joined at a first end thereof with a second end of the first
step and extending radially outward from the axis of the body by a second
distance greater than the first distance,
a third step joined at a first end thereof with a second end of the second
step and extending radially outward from the axis of the body by a third
distance greater than the second distance; and
a second end of the third step joined with a respective end of the central
shell-like portion of the bulge.
20. The golf club as set forth in claim 19, wherein the opposite ends of
the central shell-like portion are joined with respective ones of the
third steps and the central portion extends radially outward from the axis
of the body by a distance greater than the third distance.
21. The golf club as set forth in claim 19, wherein each of the first,
second and third steps extend circumferentially around the axis of the
body.
22. The golf club as set forth in claim 21, wherein the central shell-like
portion extends circumferentially around the axis of the body.
Description
BACKGROUND OF THE INVENTION
This invention relates to a golf club and a shaft therefor and particularly
relates to a golf club and a shaft therefor having structure which
increases the opportunity for making clubs of lighter weight with enhanced
flexibility and torsional characteristics.
Golfing is a world wide sport with increasing popularity. With the increase
in the golfing population, there is a significant increase in the number
of players with a discerning demand for golf clubs which will improve and
enhance their playing of the game. This demand goes well beyond those who
play professionally and those in the upper levels of the amateurs.
Typically, some of the aspects of concern for the discerning golfer are the
weight of the club, a balance between the flexibility and the stiffness of
the shaft, and the torsional character of the shaft. Golfers usually
prefer a light-weight club for obvious reasons. However, the flexibility
and torsional requirements vary amongst golfers and relate to the golfer's
"feel" of the club when the club is swung and upon impact with the ball.
In an effort to provide golf clubs which generally address the concerns
noted above, many designs of shaft configuration and composition have
evolved over the years. Some of these designs involve the placement of an
enlargement in a selected portion of the shaft to, in effect, divide the
shaft into two sections. One example of this premise regarding metal
shafts is disclosed in U.S. Pat. No. 2,050,554 which issued on Aug. 11,
1936. An example of such structure in a composite or non-metallic shaft is
disclosed in United Kingdom Patent No. GB 2,250,443 which issued on Aug.
24, 1994.
While golf clubs having shafts with a variety of such enlargement designs
have been effective, there is a continuing demand and need for further
improvement in this aspect of shaft design.
In addition, each club within a set of clubs typically has parameters which
are different from the parameters of the other clubs in the set. For
example, the club length, club weight, head configuration and other club
parameters of each of the clubs of a set is different from the same
parameters of the other clubs in the set. This equates to a different
Moment-of-Inertia and different torsional requirement for each club with
respect to each of the other clubs of the set. Therefore, each time the
golfer uses a different club from the set in the normal playing of the
game of golf, the golfer experiences different reactions from the swinging
of the various clubs of the set which could affect the consistency in the
golfer's playing of the game.
In view of this potential inconsistency, there is a need to balance or
match the clubs of a set so that torsional stability of each club is
normalized with respect to the other clubs of the set and the reaction
realized by the golfer is somewhat consistent from club to club of the
set.
SUMMARY OF THE INVENTION
It is, therefore, an object of this invention to provide a golf club, and a
shaft therefor, with improved characteristics leading to enhanced playing
of the game of golf by the users of a club employing such a shaft.
Another object of this invention is to provide a golf club shaft which is
sectionalized to enhance performance characteristics of a golf club which
employs such a shaft.
Still another object of this invention is to provide a shaft which is
adaptable for use with the different clubs of a set to provide general
uniformity and matching in the torsional characteristics of the different
clubs and thereby enhance a golfers opportunity to play the game of golf
within the normal ability of the golfer.
With these and other objects in mind, this invention contemplates a golf
club shaft which includes a metallic body extending longitudinally along
an axis of the body. The body is formed with a butt end at one end of the
body and has an inboard extremity of a prescribed diameter and an outboard
extremity. The body is further formed with a tip end at an end of the body
axially opposite the butt end and spaced axially therefrom wherein the tip
end has an inboard extremity of a diameter less than the prescribed
diameter and an outboard extremity. In addition, the body is formed with
an intermediate section which extends from the inboard extremity of the
butt end toward the tip end. The diameter of an end of the intermediate
section which joins the butt end is the same as the prescribed diameter
and the diameter of an opposite end of the intermediate section is less
than the prescribed diameter. The body is formed with a bulge along the
axis thereof. The bulge is formed with radially outward extending, axially
spaced, stepped portions which are joined with opposite ends of a central
shell-like portion which extends between the stepped portions.
This invention further contemplates a golf club which embodies the shaft
contemplated above in combination with a grip assembled on the butt end of
the shaft and a club head assembled on the tip end of the shaft.
Other objects, features and advantages of the present invention will become
more fully apparent from the following detailed description of the
preferred embodiment, the appended claims and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
FIG. 1 is a side view with portions broken away showing a golf club
including a shaft with a bulge in accordance with certain principles of
the invention;
FIG. 2 is a partial view showing the bulge of FIG. 1 in accordance with
certain principles of the invention;
FIG. 3 is a perspective view of the bulge of FIG. 2; and
FIG. 4 is a diagram showing representations of the shafts of a set of golf
clubs with the shaft of each club having a bulge formed thereon in
accordance with certain principles of the invention to match the clubs of
the set for consistent torsional performance.
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 1, a golf club 10 includes a shaft 12 which is formed in a
configuration of a hollow body or tube having a longitudinal axis 11 and
composed of steel or some other suitable metal such as, for example,
titanium. The shaft 12 is formed with an axial opening 13 therethrough.
The club 10 further includes a grip 14, shown in phantom, assembled on a
cylindrical butt end 16 of the shaft 12 and a club head 18, shown in
phantom, mounted on a cylindrical tip end 20 of the shaft. The shaft 12 is
also formed with an intermediate section 22 between the butt end 16 and
the tip end 20. It is noted that the butt end 16 and the tip end 20 are
preferably cylindrical as illustrated, but either or both ends could be
tapered without departing from the spirit and scope of the invention.
The intermediate section 22 of the shaft 12 is composed of a plurality of
cylindrical sections 22a through 22n which extend along the axis 11. The
sections 22a through 22n are of decreasing diameters from section 22a to
section 22n and each are formed at a respective length also as indicated
in the Parameter Table below. The wall thickness of the shaft 12 increases
non-uniformly from about 0.012 inch at the outboard extremity of the butt
end 16 to about 0.021 inch at the outboard extremity of the tip end 20. In
particular, the wall thickness is about 0.012 inch from the outboard
extremity of the butt end 16 generally to section 22f and gradually
increases to about 0.015 inch between sections 22f and 22i, to about 0.017
inch between sections 22i and 22n and to about 0.021 inch at the outboard
extremity of the tip end 20.
In the preferred embodiment of the invention as shown in FIG. 1, a bulge 24
is formed in the shaft 12 and is located between, and joined to, section
22n and the tip end 20. Referring to FIGS. 2 and 3, the bulge 24 is formed
with a central cylindrical section 26. The bulge 24 is formed with three
cylindrical step surfaces 30, 32 and 34 at an inboard end of the central
section and three cylindrical step surfaces 36, 38 and 40 at an outboard
end thereof. In the preferred embodiment, the diameters of the step
surfaces 30 and 40 are the same, and are greater than the diameter of the
section 22n and the tip end 20. The diameters of the step surfaces 32 and
38 are the same, and are greater than the diameter of the step surfaces 30
and 40. The diameters of the step surfaces 34 and 36 are the same, and are
greater than the diameter of the step surfaces 32 and 38. The diameters of
all of the step surfaces 30, 32, 34, 36, 38 and 40 are less than the
diameter of the central section 26 and the axial lengths of all of the
step surfaces are the same prescribed length, which is less than the
prescribed length of the central section. The wall thickness in the area
of the bulge 24 is about 0.0185 inch to 0.019 inch. The various length and
O.D. dimensions segments of the bulge 24 are also shown in the Parameter
Table below.
In the following Parameter Table, the number in the left column identifies
the segment of the preferred embodiment of the shaft 12 for which the
length and outside diameter are listed.
______________________________________
PARAMETER TABLE
Segment Length in
O.D. in
No. Inches Inches
______________________________________
16 9.00 0.600
22a 2.00 0.590
22b 1.50 0.575
22c 1.50 0.560
22d 3.00 0.545
22e 1.25 0.530
22f 1.25 0.510
22g 1.25 0.490
22h 1.25 0.470
22i 1.25 0.450
22j 1.25 0.430
22k 1.00 0.410
22l 1.00 0.390
22m 1.00 0.380
22n 0.50 0.370
30 0.50 0.385
32 0.50 0.400
34 0.50 0.415
26 1.50 0.430
36 0.50 0.415
38 0.50 0.400
40 0.50 0.385
20 10.00 0.370
12 41.00
______________________________________
The length, diameter and thickness dimensions noted above, and the
structural configurations of the drawings, are of the preferred embodiment
of the invention. Other length, diameter and thickness dimensions, and
structural configurations can be used without departing from the spirit
and scope of the invention.
In the preferred embodiment, the axial length of each of the step surfaces
30, 32, 34, 36, 38 and 40 is about one-third of the axial length of the
central cylindrical section 26. This ratio of axial lengths provides at
each end of the bulge 24 three comparatively short, but increasing,
increments of stepping between (1) the common diameter of the section 22n
and the tip end 20 and (2) the diameter of the central section 26. The
three step surfaces 30, 32 and 34 at the inboard end of the central
section 26, and the three short step surfaces 36, 38 and 40 at the
outboard end of the central section, provide strength, integrity and
support for the central section. In this manner, the central section 26
with the larger diameter and longer axial length, and the relatively long
bulge 24 in general, are well supported in a section of the shaft 12 which
includes the smallest diameter of the shaft. This allows the bulge 24 to
provide enhanced performance for the golf club 10 which employs the shaft
12.
As shown in FIG. 1, 2 and 3, in the preferred embodiment, the bulge 24 is
joined on one side to section 22n, which has the smallest diameter of any
portion of the shaft 12, and is joined on the other side thereof with the
tip end 20 which has a diameter of the same dimension as the diameter of
section 22n. However, the bulge 24 could be located totally along any part
of the intermediate section 22, the tip end 20 or a combination of the
intermediate section and the tip end without departing from the spirit and
scope of the invention.
The particular arrangement of the elements of the bulge 24 provide
structural features of the shaft 12 which enhance the performance
characteristics of the shaft when the shaft forms a portion of the golf
club 10. By placement of the bulge 24 as illustrated in FIG. 1, the center
of gravity of the club 10 is located closer to the tip end 20 of the shaft
12 than it would normally be in a bulgeless shaft. This feature permits
the use of lighter weight club heads in the assembly of a finished golf
club.
As shown in FIG. 4, the presence and selective arrangement of the elements
of the bulge 24 in a set of shafts 12 assist in the performance
optimization of the individual clubs within the related set of golf clubs.
In a matched set of golf clubs, each head exhibits unique dynamic
characteristics. The moment of inertia and, consequently, the torsional
requirements of each head within the set are different from each other.
The bulge 24 and its positioning on the shaft 12 serve to address the
torsional requirement of each head and normalize the torsional stability
of each individual club within the set. This results in the matching of
each club within the set from a torsional standpoint.
The presence of the bulge 24 in the shaft 12 serves to segment the shaft
from a flexural standpoint. The bulge 24 allows different combinations of
flexural stiffness in the portions of the shaft 12 between the bulge and
the butt end 16 on the one side, and the bulge and the tip end 20 on the
other side. The combining of different flexural stiffness with the shaft
12 contributes to a particular golf shot trajectory, depending on the
combination used. For example, if the shaft 12 is designed with both of
the abovenoted portions being flexible, the resultant golf shot trajectory
would be higher than if the shaft was designed with both portions being
fairly stiff or rigid. In accordance with the principles of this
invention, the bulge 24 allows several permutations of this concept in
order to optimize both the golf ball launch angle when struck with the
golf club 10 and the resultant golf shot trajectory.
In general, the above-identified embodiment is not to be construed as
limiting the breadth of the present invention. Modifications, and other
alternative constructions, will be apparent which are within the spirit
and scope of the invention as defined in the appended claims.
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